1. Field of the Invention
The present invention relates to a digital image processing and, more particularly, to an apparatus and a method for generating a constructively multi-patterned watermark, an apparatus and a method for inserting and detecting the watermark using the same.
2. Description of the Related Art
Digital watermarking is a technique for inserting particular information in the form of signals unrecognizable by sight or hearing, into multimedia contents such as texts, videos, static images, etc. to conceal them, and extracting the concealed information to use them as additional information for authentication of copyrights and images and for monitoring of videos.
These digital watermarking techniques include trade-off characteristics as follows.    1. Invisibility: An original image and a watermarked image should be undistinguishable by human sight.    2. Robustness: a watermark should be detectable in spite of transforms of multimedia contents such as various image processing, noises, image compression, geometric transforms, digital to analog conversion, etc.    3. Payload: As much information as possible should be able to be inserted into the same multimedia contents.
The invisibility or payload should be lowered in order to elevate the watermark robustness, while the robustness or invisibility should be lowered in order to elevate the payload.
Therefore, the digital watermarking techniques for elevating the watermark payload and watermark robustness simultaneously are being demanded.
On the other hand, various methods for withstanding geometric transforms of an image in terms of the watermark robustness has been provided, which can withstand limited transforms such as mainly rotation, image scaling, cropping or shift, etc.
However, actually novel methods for withstanding general geometric transforms as well as the limited transforms are being demanded.